Check valve in backflow prevention device

ABSTRACT

A check valve module. The check valve module includes an orifice, where the orifice is configured to allow the water flow stream through the check valve module. The check valve module also includes a clapper. The clapper is configured to allow the water flow stream through the orifice when open and prevent the water flow stream through the orifice when in a closed position by mating with the orifice. The check valve module further includes a fulcrum apparatus about which the clapper is allowed to rotate, a rotational constraint apparatus which directs the rotation of the clapper and a lateral constraint apparatus which directs the motion of the fulcrum toward and away from the orifice.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to co-pending U.S. application Ser. No.13/705,024, filed on Dec. 4, 2012, and entitled, “ACCESS COVER INBACKFLOW PREVENTION DEVICE”, which application is incorporated herein byreference in its entirety.

This application is related to co-pending U.S. application Ser. No.13/705,033, filed on Dec. 4, 2012, and entitled, “SHUTOFF VALVE INBACKFLOW PREVENTION DEVICE”, which application is incorporated herein byreference in its entirety.

BACKGROUND OF THE INVENTION

Backflow prevention devices are widely used to prevent undesirable flowreversal under low flow, static or backpressure situations wherein cleanupstream fluid sources can be contaminated by downstream fluid. Backflowprevention devices typically comprise one or two check valves, housedwithin a valve body, which undergo closure under backflow, backpressureor back siphonage conditions. The use of backflow prevention devices isgenerally required by law for cross-connected water supplies wherepotable water could undergo contamination due to flow reversal or backpressure conditions.

Currently used double check valve backflow preventers have proveddeficient in various respects. Particularly, such backflow preventersare prone to relatively high flow losses due to the valve configurationsand closure mechanisms employed, especially under low flow conditions.In particular, the motion of the check valves either causes wear overtime. Poppet valves have significantly less wear. However, theyinterrupt the flow to a higher degree.

Further, backflow preventer assemblies typically require a bulky, heavycast housing with a side port tube or extension and a separately castport cover. This type of housing is expensive to manufacture andrequires a substantial amount of space to accommodate the side port tubeand cover. Additionally, the cover typically undergoes a high amount ofpressure requiring a thicker cover with more attachment points, whichmakes maintenance move inconvenient and difficult.

In addition, backflow preventer assemblies typically require pressuremeasuring ports. These ports allow measurement of pressure in eachregion of the backflow preventer to ensure proper operation. However,these ports require space between components of the backflow preventerassembly. This results in a longer backflow preventer assembly and,therefore, more cost in manufacture and installation. Particularly, theinstallation requires more space which increases the cost.

Moreover, reducing the length results in eddies within the current whichcan reduce the accuracy of pressure measurements. Since accuracy isessential to ensure proper operation, the typical response has been tosimply refuse to shorten the length of the backflow preventer assembly.This contravenes the desire to reduce the flow length of the backflowpreventer assembly, as described above.

Additionally, the increased length and material required in manufactureincreases the weight of the backflow preventer assembly. This increasesthe difficulty in installing the backflow preventer assembly. Typicallymultiple people or an ad hoc support device are required simply to holdthe assembly in the required position during assembly. This increasesthe installation time and cost.

Accordingly, there is a need in the art for a backflow preventerassembly which is compact and light weight. Further, there is a need inthe art for a backflow preventer assembly which allows for accuratepressure measurement in each region, despite its compact nature.Moreover, there is a need in the art for a backflow preventer assemblywhich is easy and inexpensive to manufacture. Additionally, there is aneed in the art for a backflow preventer assembly which provides easyaccess to internal check valves. Likewise, there is a need in the artfor a backflow preventer assembly which has check valves with simplelow-friction closure mechanisms. Furthermore, there is a need in the artfor a backflow preventer assembly which provides low flow losses.

BRIEF SUMMARY OF SOME EXAMPLE EMBODIMENTS

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential characteristics of the claimed subject matter, nor is itintended to be used as an aid in determining the scope of the claimedsubject matter.

One example embodiment includes a backflow prevention device. Thebackflow prevention device includes a housing defining a water flowstream. The backflow prevention device also includes an upstream shutoffvalve configured to allow a user to control the water flow streamthrough the housing. The backflow prevention device further includes acheck valve module. The check valve module is located within the housingdownstream of the upstream shutoff valve. The check valve moduleincludes an orifice, where the orifice is configured to allow the waterflow stream through the check valve module. The check valve module alsoincludes a clapper. The clapper is configured to allow the water flowstream through the orifice when open and prevent the water flow streamthrough the orifice when in a closed position by mating with theorifice. The check valve module further includes a fulcrum apparatusabout which the clapper is allowed to rotate, a rotational constraintapparatus which directs the rotation of the clapper and a lateralconstraint apparatus which directs the motion of the fulcrum toward andaway from the orifice. The backflow prevention device additionallyincludes a downstream shutoff valve located downstream of the checkvalve module and configured to allow a user to control the water flowstream through the housing.

Another example embodiment includes a backflow prevention device. Thebackflow prevention device includes a housing defining a water flowstream. The backflow prevention device also includes an upstream shutoffvalve configured to allow a user to control the water flow streamthrough the housing. The backflow prevention device further includes acheck valve module. The check valve module is located within the housingdownstream of the upstream shutoff valve. The check valve moduleincludes an orifice, where the orifice is configured to allow the waterflow stream through the check valve module. The check valve module alsoincludes a clapper. The clapper is configured to allow the water flowstream through the orifice when open and prevent the water flow streamthrough the orifice when in a closed position by mating with theorifice. The check valve module further includes a fulcrum apparatusabout which the clapper is allowed to rotate, a rotational constraintapparatus which directs the rotation of the clapper and a lateralconstraint apparatus which directs the motion of the fulcrum toward andaway from the orifice. The motion of the clapper from the closedposition to the open position is a hybrid motion. The backflowprevention device additionally includes a downstream shutoff valvelocated downstream of the check valve module and configured to allow auser to control the water flow stream through the housing.

Another example embodiment includes a backflow prevention device. Thebackflow prevention device includes a housing defining a water flowstream. The backflow prevention device also includes an upstream shutoffvalve configured to allow a user to control the water flow streamthrough the housing. The backflow prevention device further includes acheck valve module. The check valve module is located within the housingdownstream of the upstream shutoff valve. The check valve moduleincludes a seat configured to mate with a portion of the housing and anorifice, where the orifice is configured to allow the water flow streamthrough the check valve module. The check valve module also includes aclapper. The clapper is configured to allow the water flow streamthrough the orifice when open and prevent the water flow stream throughthe orifice when in a closed position by mating with the orifice. Thecheck valve module further includes a fulcrum apparatus about which theclapper is allowed to rotate, a rotational constraint apparatus whichdirects the rotation of the clapper and a lateral constraint apparatuswhich directs the motion of the fulcrum toward and away from theorifice. The check valve module additionally includes a bias configuredto hold the clapper in the closed position a predetermined upstreampressure exists. The motion of the clapper from the closed position tothe open position is a hybrid motion. The backflow prevention deviceadditionally includes a downstream shutoff valve located downstream ofthe check valve module and configured to allow a user to control thewater flow stream through the housing.

These and other objects and features of the present invention willbecome more fully apparent from the following description and appendedclaims, or may be learned by the practice of the invention as set forthhereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

To further clarify various aspects of some example embodiments of thepresent invention, a more particular description of the invention willbe rendered by reference to specific embodiments thereof which areillustrated in the appended drawings. It is appreciated that thesedrawings depict only illustrated embodiments of the invention and aretherefore not to be considered limiting of its scope. The invention willbe described and explained with additional specificity and detailthrough the use of the accompanying drawings in which:

FIG. 1 illustrates an example of a double check assembly;

FIG. 2A illustrates a downstream perspective view of the example of areduced pressure assembly;

FIG. 2B illustrates an upstream perspective view of the example of areduced pressure assembly;

FIG. 3A illustrates a downstream perspective view of the cross-sectionalview of a reduced pressure assembly;

FIG. 3B illustrates an upstream perspective view of the cross-sectionalview of a reduced pressure assembly;

FIG. 4A illustrates an exploded top perspective view of the opening of abackflow prevention device;

FIG. 4B illustrates a top view of the opening of a backflow preventiondevice without the cover;

FIG. 5A illustrates a downstream top perspective view of the example ofa check valve module;

FIG. 5B illustrates a downstream bottom perspective view of the exampleof a check valve module;

FIG. 5C illustrates a side view of the example of a check valve module;

FIG. 6A illustrates an example of a check valve module 302 in a closedposition;

FIG. 6B illustrates an upstream perspective view of an example of acheck valve module in a semi-opened position;

FIG. 6C illustrates a side view of an example of a check valve module ina semi-opened position;

FIG. 7A illustrates a downstream bottom perspective view of analternative example of a check valve module;

FIG. 7B illustrates an upstream top perspective view of the alternativeexample of a check valve module;

FIG. 7C illustrates a side view of the alternative example of a checkvalve module; and

FIG. 8 illustrates an example of a shutoff valve.

DETAILED DESCRIPTION OF SOME EXAMPLE EMBODIMENTS

Reference will now be made to the figures wherein like structures willbe provided with like reference designations. It is understood that thefigures are diagrammatic and schematic representations of someembodiments of the invention, and are not limiting of the presentinvention, nor are they necessarily drawn to scale.

FIG. 1 illustrates an example of a double check assembly 100. In atleast one implementation, the double check assembly 100 includes twocheck valves, which allow flow in one direction, but prevent flow in theopposite direction. The double check assembly is one example of abackflow prevention device which is configured to protect water suppliesfrom contamination. In particular, the double check assembly 100 caninclude a backflow prevention redundancy. I.e., one check valve willstill act, even if the other is jammed wide open.

FIG. 1 shows that the double check assembly 100 can include a housing102. In at least one implementation, the housing 102 is configured tocontain the water flow within the double check assembly 100. I.e., thehousing 102 must be of sufficient strength to ensure that the doublecheck assembly 100 can withstand the pressure of the water supply.Additionally or alternatively, the housing 102 is configured to alignthe other components of the double check assembly 100. I.e., the housing102 can allow the internal and external components of the double checkassembly 100 to be installed and proper spacing to be maintained amongthe components.

FIG. 1 also shows that the double check assembly 100 can include aninlet 104. In at least one implementation, the inlet 104 is configuredto receive a water supply. I.e., the inlet 104 can be connected to awater supply and receive the water flow. In particular, the inlet 104can include one or more coupling mechanisms which allow the double checkassembly 100 to be connected to pipes, hoses or other devices which areconfigured to supply water. For example, the inlet 104 can includethreading, grooves, flanges or other structures which allow attachmentto the water supply.

FIG. 1 further shows that the double check assembly 100 can include anoutlet 106. In at least one implementation, the outlet 106 is configuredto output water. I.e., the outlet 106 can be connected as a water supplyto a building or other area. In particular, the outlet 106 can includeone or more coupling mechanisms which allow the double check assembly tobe connected to pipes, hoses or other devices which are configured toreceive water. For example, the outlet 106 can include threading,grooves, flanges or other structures which allow attachment to the wateroutput.

FIG. 1 additionally shows that the double check assembly 100 can includean upstream shutoff valve 108 a and a downstream shutoff valve 108 b(collectively “shutoff valves 108”). In at least one implementation, theshutoff valves 108 can be used to control or regulate water flow throughthe double check assembly 100. I.e., a user can close the upstreamshutoff valve 108 a, the downstream shutoff valve 108 b or both asneeded to control water flow. For example, closure of the upstream anddownstream shutoff valves 108 a can allow maintenance of the doublecheck assembly 100. Additionally or alternatively, shutoff of thedownstream valve can allow a user to shutoff water supply to the pipe,hose or other device connected to the outlet 106 and, therefore, anybuilding or structure receiving the water supply. One of skill in theart will appreciate that the shutoff valves 108 can be located withinthe housing or can be external to the housing, as desired.

FIG. 1 moreover shows that the upstream shutoff valve 108 a and thedownstream shutoff valve 108 b can include a first control 110 a and asecond control 110 a (collectively “controls 110”), respectively. In atleast one implementation, the controls 110 can allow a user to open orclose the shutoff valves 108. I.e., the controls 110 can include ahandle or other device which allows a user to either close or open theshutoff valve, as desired. Additionally or alternatively, the controls110 a can include a wired switch or sensor to connect the controls 110to an alarm. In particular, the switch or sensor connected to thecontrols 110 can signal an alarm if either of the shut-off valves 108 isin the opened or closed position.

FIG. 1 also shows that the double check assembly 100 can include a cover112. In at least one implementation, the cover 112 can be configured toclose an access port in the housing 102. In particular, the cover 112can be removed to allow maintenance or replacement of components withinthe housing 102. I.e., a user can remove the cover 112 to accessportions of the double check assembly 100, as described below.

FIGS. 2A and 2B illustrate an example of a reduced pressure assembly200. FIG. 2A illustrates a downstream perspective view of the example ofa reduced pressure assembly 200; and FIG. 2B illustrates an upstreamperspective view of the example of a reduced pressure assembly 200. Inat least one implementation, the reduced pressure assembly 200 includestwo check valves, which allow water flow in one direction, but preventwater flow in the opposite direction. The reduced pressure assembly 200is another example of a backflow prevention device which is configuredto protect water supplies from contamination. In particular, the reducedpressure assembly 200 can include a backflow prevention redundancy.I.e., one check valve will still act, even if the other is jammed wideopen. Additionally, a reduced pressure assembly 200 can include a firstpressure zone and a second pressure zone on either end of the upstreamcheck valve, maintained at a pressure that is lower than the watersupply pressure, but high enough to be useful downstream. The pressuredifferential between the first pressure zone and the second pressurezone can be monitored, as described below.

FIGS. 2A and 2B further show that the reduced pressure assembly 200 caninclude a relief valve 202. In at least one implementation, the reliefvalve 202 can indicate if one or more components of the reduced pressureassembly 200 have failed. In particular, different zones within thereduced pressure assembly 200 have different pressures under normaloperating conditions. If the pressure differential is disturbed, therelief valve 202 will open and discharge water to atmosphere serving asan indication of the failure.

FIGS. 2A and 2B additionally show that the reduced pressure assembly 200can include one or more sensing ports 204. In at least oneimplementation, the one or more sensing ports 204 can allow the pressurein areas of the reduced pressure assembly 200 to be checked or tested.I.e., the one or more sensing ports 204 allow for the connection of amechanical, hydraulic or electronic device which can measure thepressure in the zone to which the sensing port 204 is attached.

FIGS. 3A and 3B illustrate a cross-sectional view of a reduced pressureassembly 200. FIG. 3A illustrates a downstream perspective view of thecross-sectional view of a reduced pressure assembly 200; and FIG. 3Billustrates an upstream perspective view of the cross-sectional view ofa reduced pressure assembly 200. One of skill in the art will appreciatethat much of the discussion of FIGS. 3A and 3B will be equallyapplicable to a double check assembly, such as the double check assembly100 of FIG. 1. In at least one implementation, the reduced pressureassembly 200 allows forward flow when upstream pressure is greater thandownstream pressure. In contrast, the reduced pressure assembly 200prevents backward flow when downstream pressure is greater than upstreampressure.

FIGS. 3A and 3B show that the reduced pressure assembly 200 can includean upstream check valve module 302 a and a downstream check valve module302 b (collectively “check valve modules 302”). In at least oneimplementation, the check valve modules 302 can prevent reverse flowwithin the reduced pressure assembly 200. I.e., the check valve modules302 can be configured to allow water to flow in a forward direction(left to right as shown in FIGS. 3A and 3B) and prevent water flow inthe reverse direction (right to left as shown in FIGS. 3A and 3B).

FIGS. 3A and 3B also show that the reduced pressure assembly 200 caninclude a check retainer 304. In at least one implementation, the checkretainer 304 is configured to prevent motion of the upstream check valvemodule 302 a toward the downstream check valve module 302 b and viceversa. In particular, the check retainer 304 resists lateral forces butcan be disconnected from the housing 102 and/or removed through theaccess port in the housing 102. Removal of the check retainer 304 canallow for removal of the upstream check valve module 302 a and/or thedownstream check valve module 302 b, as desired.

FIGS. 3A and 3B further show that the reduced pressure assembly 200 caninclude an upstream receptacle 306 a and a downstream receptacle 306 b(collectively “receptacles 306”). In at least one implementation, theupstream receptacle 306 a and the downstream receptacle 306 b can beconfigured to receive the upstream check valve module 302 a and thedownstream check valve module 302 b, respectively. Additionally oralternatively, the receptacles 306 prevent movement of the check valvemodules 302 away from one another. For example, the receptacles 306 caninclude a portion of the housing which includes a narrower innerdiameter relative to a nearby location, such that a portion of the checkvalve modules 302 cannot be inserted. I.e., the receptacles 306 caninclude a lip or other feature which prevents over insertion of thecheck valve modules 302.

FIGS. 3A and 3B additionally show that the check valve modules 302 caninclude a flat portion 308. In at least one implementation, the flatportion 308 is configured to prevent rotation of the check valve modules302 relative to the receptacles 306. I.e., the flat portion 308 canensure that the check valve modules 302 fit in only one manner withinthe compartments 106. One of skill in the art will appreciate that theflat portion 308 is exemplary only and that other mechanisms forpreventing rotation are contemplated herein.

FIGS. 3A and 3B moreover show that the shutoff valves 108 can allow auser to prevent flow through either the inlet 104, the outlet 106 orboth. In at least one implementation, the shutoff valve 108 cansealingly engage the housing 102 in a closed position, which preventswater flow through the housing 102. I.e., the shutoff valves 108 canform a seal with the housing 102 which prevents all flow in bothdirections, as described below.

FIGS. 3A and 3B also show that the relief valve 202 can include asensing line 310. In at least one implementation, the sensing line 310can connect to the volume between the upstream shutoff valve 108 a andthe upstream check valve module 302 a, a first pressure zone 312 a, andthe relief valve 202. The relief valve 202 is likewise connected to thevolume between the upstream check valve module 302 a and the downstreamcheck valve module 302 b, a second pressure zone 312 b. In at least oneimplementation, the water flow will lose pressure as it flows throughthe upstream check valve 302 a. I.e., the first pressure zone 312 a, bydesign, has a higher pressure than the second pressure zone 312 b whenwater is flowing in the forward direction. For example, the firstpressure zone 312 a can be approximately 40 psi and the second pressurezone 312 b can be approximately 33 psi resulting in a pressuredifferential of approximately 7 psi. As used in the specification andthe claims, the term approximately shall mean that the value is within10% of the stated value, unless otherwise specified. If the pressureloss or differential between the first pressure zone 312 a and secondpressure zone 312 b decreases below a predetermined threshold the reliefvalve 202 will discharge, which is an indication that the upstream checkvalve module 302 a has failed or that a backflow condition is occurring.

FIGS. 3A and 3B further show that the reduced pressure assembly 200 caninclude a flow plate 314. In at least one implementation, the flow plate314 can modify the flow near the upstream check valve module 302 a. Forexample, the flow plate 314 can include an opening that allows themajority of the flow to pass through the flow plate 314 and a blockagethat stops a portion of the flow near the intake of the relief valve202. Additionally or alternatively, the flow plate 314 can include ablockage place over a portion of the opening in the check valve module302. The blockage can ensure that the relief valve 202 is notsusceptible to eddies, currents, or pressure fluctuations caused withinthe housing 102 during operational conditions, but instead sensesconsistent and steady pressure in the first pressure zone 312 a. Theflow plate 314 can be attached to the housing 102 or secured in someother way. For example, the flow plate 314 can be secured in position bythe mating of the upstream check valve module 302 a and the housing 102.

FIGS. 4A and 4B illustrate an opening 400 of a backflow preventiondevice. FIG. 4A illustrates an exploded top perspective view of theopening 400 of a backflow prevention device; and FIG. 4B illustrates atop view of the opening 400 of a backflow prevention device without thecover 112. In at least one implementation, opening 400 can allow a userto access the interior of the backflow prevention device. I.e., theopening 400 can allow the user to access portions of the backflowprevention device which are normally inaccessible, either to ensureproper operation or to perform maintenance. For example, the opening 400can allow a user to remove or install either of the check valve modules302.

FIGS. 4A and 4B show that the opening 400 can include an access port402. In at least one implementation, the access port can include asegment of the housing 102 which is open. I.e., a portion of the housing102 can be missing, forming the access port 402. The access port 402 canallow the removal or insertion of components of the backflow preventiondevice or can allow the components to be checked or maintained. Forexample, the access port 402 can be a similar width as the housing 102.I.e., the access port 402 can include a portion of a half cylinder ofthe housing 102 which is not present.

FIGS. 4A and 4B also show that the opening 400 can include a cover mount404. In at least one implementation, the cover mount 404 can allow acover to be attached, as described below. In particular, the cover mount404 can form or be proximate to the sides of the access port 402. I.e.,the cover mount 404 can be located at antipodal points along the housing102 near the access port 402. An antipodal point of a point on thesurface of a circle is the point which is diametrically opposite toit—so situated that a line drawn from the one to the other passesthrough the center of the circle and forms a true diameter.

FIGS. 4A and 4B further show that the opening 400 can include a cover112. In at least one implementation, the cover 112 has a bend orcurvature to it, with the radius of curvature being larger than theradius of curvature of the housing 102 at the opening 400. For example,the cover 112 can include a portion of a lateral surface of a rightcylinder. The lateral surface of a cylinder includes the curved portionof the cylinder. I.e., the outer surface of the cylinder excluding thebases. The cylinder need not be a circular cylinder. I.e., the cylindercan include an elliptical cylinder, an extruded polygon or otherwiseinclude straight edges, as desired.

One of skill in the art will appreciate that adding curvature to thecover 112 creates tangential tensile stresses when under pressure ratherthan bending moment stresses, typical of flat covers of similar purpose.I.e., the convex nature of the cover 112 allows the cover 112 toequalize the pressure over the entire surface, allowing the cover 112 tobe thinner than if the cover 112 were flat. That is, a flat cover 112would deform, to some degree, under pressure. In contrast, the curvaturereduces the deformation of the cover 112. Additionally or alternatively,the force imparted by the water within the housing is less likely tocause separation of the cover 112 from the housing 102.

FIGS. 4A and 4B additionally show that the opening 400 can include anattachment 406. In at least one implementation, the attachment 406 isconfigured to attach the cover 112 to the cover mount 404. For example,the attachment 406 can include bolts, screws, clips, clamps or any otherdesired attachment. One of skill in the art will appreciate that theattachment 406 can be secured along the edges of the cover 112. I.e., nosupport structure is necessary within the access port 402, allowing auser to more easily access the interior portions of the backflowprevention device. One of skill in the art will further appreciate thatthe curvature of the cover 112 allows the cover 112 to cover a longerdistance without requiring the thickness of a flat cover. That is, thesame thickness of cover 112 can have a longer distance betweenattachments 406 because of the curvature of cover 112 relative to a flatcover 112.

FIGS. 4A and 4B moreover show that the opening 400 can include a seal408. In at least one implementation, the seal 408 can sealingly engagethe cover 112 and the housing 102 along the perimeter of the cover 112.That is, the seal 408 can provide a water tight connection between thecover 112 and the housing 112 when the cover is attached such that wateris prevented from leaking out the cover 112 when water flows through thehousing 102. For example, the seal 408 can include an elastomer or othercompressible material.

FIGS. 5A, 5B and 5C illustrate an example of a check valve module 302.FIG. 5A illustrates a downstream top perspective view of the example ofa check valve module 302; FIG. 5B illustrates a downstream bottomperspective view of the example of a check valve module 302; and FIG. 5Cillustrates a side view of the example of a check valve module 302. Inat least one implementation, the check valve module 302 is configured toallow fluid flow in only one direction. That is, the check valve module302 allows fluid to flow in one direction but blocks fluid flow in theopposite direction. Preventing reverse fluid flow can preventcontamination of the fluid source and/or prevent damage from highpressure caused by reverse flow.

FIGS. 5A, 5B and 5C show that the check valve module 302 can include aclapper 502. In at least one implementation, the clapper 502 isconfigured to completely block the flow through the check valve module302 when closed. In contrast, the clapper 502 is configured to allow asmuch flow as possible through the check valve module 302 when opened, asdescribed below. In particular, the clapper 502 can include a largesurface area which is placed perpendicular to the flow when in a closedposition and a small profile or cross-sectional area which is placedwithin the flow when in an open position.

FIGS. 5A, 5B and 5C also show that the check valve module 302 caninclude a seat 504. In at least one implementation, the seat 504 isconfigured to mate with a portion of the housing in a backflowprevention device. For example, the seat 504 can be configured to matewith a compartment, such as the receptacles 306 of FIGS. 3A and 3B. Theseat 504 can include one or more features to ensure proper orientation,such as a notch, a protrusion, a flat portion or any other feature whichmates with the housing of the backflow prevention device.

FIGS. 5A, 5B and 5C further show that the check valve module 302 caninclude an orifice 506. In at least one implementation, the orifice 506can include an opening through the seat 504 through which water canflow. I.e., the orifice 506 can allow water to flow when the clapper 502is in the open position. Likewise, the orifice 506 can include a lip orother feature to create a seal with the clapper 502 in the closedposition, as described below.

FIGS. 5A, 5B and 5C additionally show that the check valve module 302can include a seal 508. In at least one implementation, the seal 508 isconfigured to prevent any leakage at the joint between the seat 504 andthe housing of the backflow prevention device. For example, the seal 508can include an O-ring. In at least one implementation, an O-ring, alsoknown as a packing, or a toric joint, is a mechanical gasket in theshape of a torus. I.e., it is a loop of elastomer with a disc-shapedcross-section, designed to be seated in the groove and compressed duringassembly between two or more parts, creating a seal at the interface.

FIGS. 5A, 5B and 5C moreover show that the clapper 502 can include anelastomer disk 510. In at least one implementation, the elastomer disk510 can allow a seal between the clapper 502 and the seat 504 when theclapper 502 is in the closed position. In particular, the elastomer disk510 can be pressed against the seat 504 to prevent any water leakagewhen the clapper 502 is in the closed position. For example, theelastomer disk 510 can be pressed against a lip or other feature of theorifice 506, as described above.

FIGS. 5A, 5B and 5C also show that the check valve module 302 caninclude a stop 512. In at least one implementation, the stop 512 canprevent over insertion of the check valve module 302. I.e., as the checkvalve module 302 is pressed into the housing of a backflow preventiondevice, the stop 512 comes in contact with a portion of the housing,preventing further insertion of the check valve module 302.

FIGS. 5A, 5B and 5C further show that the check valve module 302 caninclude a lateral constraint apparatus 514. In at least oneimplementation, the lateral constraint apparatus 514 can guide themotion of the clapper 502. I.e., the lateral constraint apparatus 514can direct the motion of a rotational axis 516 when transitioning fromthe open position to the closed position or vice versa. In particular,the lateral constraint apparatus 514 can direct the motion of the axis516 toward and away from the orifice 506. The lateral constraintapparatus 514 can be secured to the seat 504 such that the lateralconstraint apparatus 514 is sufficiently durable to resist lateralmotion of the clapper 502.

FIGS. 5A, 5B and 5C additionally show that the check valve module 302can include the axis 516. In at least one implementation, the axis 516can include a line about which the clapper 502 rotates. That is, theaxis 516 can include an attachment point about which the clapper 502rotates. For example, the axis 516 can include a hinge, pin, rod or anyother desired mechanism. The axis 516 can move laterally relative to theseat 504 along the lateral constraint apparatus. In particular, thelateral constraint apparatus can allow motion of the axis 516 toward andaway from the opening of the seat 504 when the clapper 502 is eitherclosing or opening, respectively.

FIGS. 5A, 5B and 5C moreover show that the lateral constraint apparatus514 can include a guide 518. In at least one implementation, the guide518 can extend perpendicularly from the seat 504. For example, the guide518 can include rods or shafts attached to the seat 504. The guide 518can be of sufficient strength to ensure that the clapper 502 can besupported within the flow stream and to resist force acting on theclapper 502 during operating conditions.

FIGS. 5A, 5B and 5C also show that the lateral constraint apparatus 514can include a fulcrum apparatus 520. In at least one implementation, thefulcrum apparatus 520 can attach the clapper 502 to the guide 518. Inparticular, the fulcrum apparatus 520 can move relative to the guide 518in a direction determined or controlled by the guide 518. That is, thefulcrum apparatus 520 can constrain the attachment point of the clapper502 to move laterally toward or away from the seat 504, while stillallowing the clapper 502 to rotate about axis 516, as described below.For example, the fulcrum apparatus 514 can include a pin, configured todirect the rotation of the clapper 502. Additionally or alternatively,the fulcrum apparatus 514 can include a receiver attached to the lateralconstraint apparatus 514

FIGS. 5A, 5B and 5C further show that the check valve module 302 caninclude a rotational constraint apparatus 522. In at least oneimplementation, the rotational constraint apparatus 522 can connect theclapper 502 and the seat 504. In particular, the rotational constraintapparatus 522 can cause the clapper 502 to rotate relative to the seat504. I.e., the rotational constraint apparatus 522 controls therotational motion of the clapper 502 during the opening or closing ofthe clapper 502.

FIGS. 5A, 5B and 5C additionally show that the rotational constraintapparatus 522 can include a rotational linkage 524. In at least oneimplementation, the rotational linkage 524 can cause the clapper 502 torotate when opening. I.e., the rotational linkage 524 can cause aportion of the clapper 502 to remain closer to the seat 504 than anotherportion of the clapper 502, inducing a rotational motion in the clapper502 about axis 516. For example, the rotational linkage 524 can beattached to a position offset relative to the axis 516 on the clapper502. That is, the rotational linkage 524 can be attached at a locationother than the center point of the clapper 502.

FIGS. 5A, 5B and 5C moreover show that rotational constraint apparatus522 can include a boss 526. In at least one implementation, the boss 526is in contact with the rotational constraint apparatus 522 to allow therotational constraint apparatus 522 to direct the opening or closing ofthe clapper 502. In particular, the boss 526 includes a clasp means orhinge. That is, the linkage 502 is attached to the boss 526 but canrotate relative to the boss 526.

FIGS. 5A, 5B and 5C also show that the check valve module 302 caninclude a bias 528. In at least one implementation, the bias 528 can beconfigured to hold the clapper 502 in the closed position. I.e., thebias 528 can push the clapper 502 toward the seat 504 absent anotherforce. The bias 528 can constrain the clapper 502 to remain closedunless an upstream pressure exists which is greater than a predeterminedthreshold, allowing flow of water through the check valve module 302,called the opening point of the check valve module. I.e., the bias 528predisposes the check valve module 302 such that the upstream pressuremust exceed the downstream pressure by a predetermined amount before theclapper 502 will open. For example, the bias 528 can include a spring orother mechanism which provides a closing force on the clapper 502.

One of skill in the art will appreciate that the location of therotational constraint apparatus 522, the lateral constraint apparatus514, the fulcrum apparatus 520 and the bias 528 are exemplary only. Thatis, any combination of mechanisms which provides a rotational constraintand a linear constraint on the motion of the clapper 502 along with abias mechanism to keep the clapper 502 predisposed to the closedposition are contemplated herein, unless otherwise specified in theclaims.

FIGS. 6A, 6B and 6C show that the clapper 502 undergoes a hybridmovement. FIG. 6A illustrates an example of a check valve module 302 ina closed position; FIG. 6B illustrates an upstream perspective view ofan example of a check valve module 302 in a semi-opened position; andFIG. 6C illustrates a side view of an example of a check valve module302 in a semi-opened position. I.e., the clapper 502 is neither a poppet(linear motion), nor a swing check (rotational motion), but a hybrid ofthe two. This utilizes the advantages of both movement types, whileeliminating many of the drawbacks associated with both movement types.

In a poppet valve, instead of sliding or rocking over a seat to uncovera port or seat, the poppet valve lifts from the seat with a movementperpendicular to the port or seat. The main advantage of the poppetvalve is that the elastomer disk 510 of the clapper 502 has no lateralmovement on the seat 504, thus reducing the wear on the elastomer disk510 and increasing the life cycle of the check valve module 302. Inaddition, the force applied to the clapper 502 during this poppet stylemotion is balanced and linear providing more consistent force at theopening point of the check valve module. I.e., less force is needed tomove the poppet because some forces on the poppet are nullified by equaland opposite forces. I.e., the opening force has to counteract only aspring or other biasing force. However, the poppet valve has asignificant disadvantage in that the clapper 502 remains in the middleof the water flow. That is, the water must flow around a poppet valvewhich causes severe pressure loss and/or friction loss through thebackflow preventer under normal operating conditions.

In a swing check valve or tilting disc check valve, the movable part orclapper 502 necessary to block or control the flow, swings on avirtually fixed axis hinge or trunnion, either onto the seat 504 toblock reverse flow or off the seat 504 to allow forward flow. That is,the clapper 502 is attached to the seat 504 by a hinge, about which theclapper 502 rotates. Because the clapper 502 rotates, the clapper 502presents a thinner cross-sectional area within the water flow when inthe open position. That is, a swing check valve offers less resistanceto water flow or pressure loss through the check valve module 302.However, the swing check valve includes lateral motion between theelastomer disk 510 and the seat 504 as the clapper approaches the closedposition, which eventually causes the seal to fail. In addition, themechanisms associated with the closing force or closing bias of swingcheck valves are inherently more complex and, therefore, have greatermechanical system friction and inconsistencies than poppet style checkvalves. This results, in turn, in inconsistencies of critical checkvalve opening points associated with backflow prevention valves.

In contrast, in the current implementation utilizes a hybrid motion.I.e., the clapper 502 moves approximately perpendicularly and linearlyaway from the seat 504 when it initially opens. The clapper 502 thenbegins to rotate, minimizing the surface area interrupting fluid flow.This provides numerous benefits including; consistent closure forceresulting in consistent static pressure differential across the checkvalve (critical to the functionality of all backflow preventers); lesssusceptibility to fouling at the elastomer disk 510 and valve seat 504;excellent pressure loss or friction loss under high flow conditions; andno mechanical advantage or differentially loaded mechanism so there areno low flow pressure fluctuations resulting in system alarm failures.

FIGS. 7A, 7B and 7C illustrate an alternative example of a check valvemodule 302. FIG. 7A illustrates a downstream bottom perspective view ofthe alternative example of a check valve module; FIG. 7B illustrates anupstream top perspective view of the alternative example of a checkvalve module; and FIG. 7C illustrates a side view of the alternativeexample of a check valve module. In at least one implementation, thealternative example of a check valve module 302 can allow for a decreasein the closing bias force as the clapper 502 transitions from fullyclosed to fully open. That is, that the closing bias force on theclapper 502 is stronger the closer the clapper is to the closedposition, as discussed below.

FIGS. 7A, 7B and 7C show that the lateral constraint apparatus 514 caninclude a slot 702. In at least one implementation, the slot 702 can bearranged perpendicularly relative to the seat 504. The slot 702 can beof sufficient strength to ensure that the clapper 502 can be supportedwithin the flow stream and to resist force acting on the clapper 502during operating conditions. In particular, the slot 702 can allow therotational axis 516 to move laterally toward and away from the seat 504.

FIGS. 7A, 7B and 7C also show that the check valve module 302 caninclude a fulcrum apparatus 704. In at least one implementation, thefulcrum apparatus 704 can attach the clapper 502 to the lateralconstraint apparatus 514. In particular, the fulcrum apparatus 704 canmove relative to the lateral constraint apparatus 514 in a directiondetermined or controlled by the lateral constraint apparatus 514. Thatis, the fulcrum apparatus 704 can constrain the attachment point of theclapper 502 to move laterally toward or away from the seat 504, whilestill allowing the clapper 502 to rotate about axis 516 of the pin 706.

FIGS. 7A, 7B and 7C further show that the fulcrum apparatus 704 caninclude a pin 706. In at least one implementation, the pin 706 can beplaced within the slot 702 to act as the rotational axis 516. Inparticular, a portion of the pin 706 can extend through the slot 702 andbe secured. The pin 706 is then allowed to move and rotate relative tothe slot 702 but is retained within the slot 702.

FIGS. 7A, 7B and 7C additionally show that the fulcrum apparatus 704 caninclude a roller 708. In at least one implementation, the roller 708 cansecure the pin 706 within the slot 702. I.e., the roller 708 can ensurethat a portion of the pin 706 remains within the slot 702. Additionallyor alternatively, the roller 708 can allow the pin 706 to rotaterelative to the slot 702. I.e., the roller 708 can allow the pin 706 torotate freely within the slot 702.

FIGS. 7A, 7B and 7C moreover show that the fulcrum apparatus 704 caninclude an attachment 710. In at least one implementation, theattachment 710 can secure the pin 706 to the clapper 502. For example,the attachment 710 can include a hole that extends partially orcompletely into the clapper 502. In particular, the hole 710 can allowthe clapper 502 to rotate about the rotational axis 516 created by thepin 706.

FIGS. 7A, 7B and 7C also show that the bias 528 can include a torsionspring 712. In at least one implementation, the torsion spring 712 is aspring that works by torsion or twisting. That is, the torsion spring712 includes a flexible elastic object that stores mechanical energywhen it is twisted. When it is twisted, it exerts a force (actuallytorque) in the opposite direction, proportional to the amount (angle) itis twisted. As the clapper 502 opens, the distance and angle of forceexerted by the torsion spring 712 are changed, decreasing the closingbias and lessening the distortion on the fluid flow due to closing bias.

FIGS. 7A, 7B and 7C further show that the bias 528 can include a firstlinkage 714. In at least one implementation, the first linkage 714allows the torsion spring 712 to produce a force acting on the clapper502. That is, the torsion spring 512 provides a rotational force that isclose in proximity to the torsion spring 512. The first linkage 714 canconvert the rotational force produced by the torsion spring 712 to alinear force that acts remotely relative to the torsion spring 512 onthe clapper 502, maintaining a closing force on the clapper 502.

FIGS. 7A, 7B and 7C additionally show that the bias 528 can include asecond linkage 716. In at least one implementation, the second linkage716 can be attached to the first linkage 714 to transfer force from thetorsion spring 512 to the clapper 502. I.e., the second linkage 716 canbe attached to a position on the clapper 502. Because the first linkage714 and the second linkage 716 are allowed to move relative to oneanother they transfer the rotational force of the torsion spring 512 toa linear closing force on the clapper 502. One of skill in the art willappreciate that the second linkage 716 can be attached to a positionoffset relative to the axis 516 on the clapper 502. That is, the secondlinkage 716 can be attached at a location other than the center point ofthe clapper 502.

FIGS. 7A, 7B and 7C moreover show that the rotational constraintapparatus 522 can include a boss 526. In at least one implementation,the boss 526 is in contact with the rotational constraint apparatus 522to allow the rotational constraint apparatus 522 to direct the openingor closing of the clapper 502. In particular, the boss 526 includes aclasp means or hinge. That is, the rotational linkage 524 is attached tothe boss 526 but can rotate relative to the boss 526.

FIGS. 7A, 7B and 7C also show that the rotational constraint apparatus522 can include a rotational linkage 524. In at least oneimplementation, the rotational linkage 524 can cause the clapper 502 torotate when opening. I.e., the rotational linkage 524 can cause aportion of the clapper 502 to remain closer to the seat 504 than anotherportion of the clapper 502, inducing a rotational motion in the clapper502 about axis 516.

FIGS. 7A, 7B and 7C further show that the rotational constraintapparatus 522 can include an attachment 718. In at least oneimplementation, the attachment 718 can connect the rotational linkage524 to the clapper 502. For example, the attachment 718 can include apin or other desired mechanism. One of skill in the art will appreciatethat the attachment 718 can connect the rotational linkage 524 to aposition offset relative to the axis 516 on the clapper 502. That is,the rotational linkage 524 can be attached at a location other than thecenter point of the clapper 502.

FIG. 8 illustrates an example of a shutoff valve 108. In at least oneimplementation, the shutoff valve 108 can prevent all fluid flow. Thatis, the shutoff valve 108 can form a seal with the housing, 102preventing all water flow through the backflow prevention device. Forexample, the shutoff valve 108 can be used to test the backflowprevention device or to perform maintenance on the backflow preventiondevice.

FIG. 8 also shows that the shutoff valve 108 can include a obstruction802. In at least one implementation, the obstruction 802 can beconfigured to mate with the internal surface of the housing 102. I.e.,the obstruction 802 can be placed perpendicular to the flow, preventingflow within the housing 102. In contrast, when the obstruction 802 isaligned parallel to the flow, the water can flow freely through thehousing 102. For example, the obstruction 802 can include a disk orotherwise be shaped to match the internal shape of the housing 102.

FIG. 8 shows that the shutoff valve 108 can include a rotating means804. In at least one implementation, the rotating means 804 can connectthe obstruction 802 to the control 110. I.e., a user can use the control110 to move the rotating means 804, which moves the obstruction 802 intothe desired position. That is, rotation of the rotating means 804results in rotation of the obstruction 802. For example, the rotatingmeans 804 can include a shaft or other device.

In at least one implementation, the obstruction 802 can be a sphericalsegment. A spherical segment is the portion of a sphere cut off by twoparallel planes. I.e., the edges of the obstruction 802 can be curved,forming the outer portion of a sphere. In particular, the obstruction802 can include a spherical segment of a sphere with a diameter that isconcurrent with the axis of the rotating means 804. Using a sphericalsegment as the obstruction 802 can allow the obstruction 802 to rotate360 degrees within the housing 102.

FIG. 8 further shows that the housing 102 can include a sealing surface806. In at least one implementation, the sealing surface 806 can be asection of the housing 102 which is configured to receive theobstruction 802 in the closed position. In particular, the sealingsurface 806 can include a curved surface equivalent to a sphericalsegment. That is, the sealing surface 806 can be configured to mate withthe obstruction 802 when in the closed position.

FIG. 8 additionally shows that the obstruction 802 can include a seal808. In at least one implementation, the seal 808 can be configured toensure drip tight mating between the obstruction 802 and the seat 806.I.e., the seal 808 can ensure that water does not leak past theobstruction 802 when in the closed position. For example, the seal 808can include an O-ring or other compressible material.

In at least one implementation, the engagement between the seal 808 andthe sealing surface 806 can be offset relative to the axis of therotating means 804. I.e., the engagement between the seal 808 and thesealing surface 806 can be entirely located downstream of the axis ofthe rotating means 804 in the upstream shutoff valve 108 a of FIG. 1 andcan be entirely located upstream of the axis of the rotting means 804 inthe downstream shutoff valve 108 b of FIG. 1. For example, theobstruction 802 can be mounted on the side of the rotating means 804.

Offsetting the engagement between the seal 808 and the sealing surface806 relative to the rotating means 804 can allow the backflow preventiondevice to have an overall shorter laylength. In particular, the sealingpoint of the obstruction 802 with the housing can be closer to theupstream check valve module, which can, in turn, allow additional spacebetween the inlet of the backflow preventer and the sealing point of theobstruction of the upstream shutoff valve 108 a for the industryrequired sensing port. This additional space allows for a shorterlaylength of the backflow preventer thus reducing installation andmanufacturing costs. Specifically, the sensing port can be parallel tothe rotating means 804 rather that upstream or downstream of therotating means 804.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of the invention is, therefore, indicatedby the appended claims rather than by the foregoing description. Allchanges which come within the meaning and range of equivalency of theclaims are to be embraced within their scope.

What is claimed is:
 1. A backflow prevention device, the backflowprevention device comprising: a housing defining a water flow stream; anupstream shutoff valve, wherein the upstream shutoff valve is configuredto allow a user to control the water flow stream through the housing; acheck valve module: located within the housing downstream of theupstream shutoff valve; and including: an orifice, wherein the orificeis configured to allow the water flow stream through the check valvemodule; a clapper, wherein the clapper is configured to: allow the waterflow stream through the orifice when open; and prevent the water flowstream through the orifice when in a closed position by mating with theorifice; a fulcrum apparatus about which the clapper is allowed torotate; a rotational constraint apparatus which directs the rotation ofthe clapper; and a lateral constraint apparatus constrains the fulcrumapparatus to move upstream and downstream relative to the orifice; adownstream shutoff valve: located downstream of the check valve module;and configured to allow a user to control the water flow stream throughthe housing.
 2. The backflow prevention device of claim 1 furthercomprising a second check valve module including: an orifice, whereinthe orifice is configured to allow the water flow stream through thesecond check valve module; a clapper, wherein the clapper is configuredto: allow the water flow stream through the orifice when open; andprevent the water flow stream through the orifice when in a closedposition by mating with the orifice; a fulcrum apparatus about which theclapper is allowed to rotate; a rotational constraint apparatus whichdirects the rotation of the clapper; and a lateral constraint apparatuswhich directs the motion of the fulcrum toward and away from theorifice.
 3. The backflow prevention device of claim 2, wherein thesecond check valve module is located within the housing upstream of thecheck valve module.
 4. The backflow prevention device of claim 2,wherein the second check valve module is located within the housingdownstream of the check valve module.
 5. The backflow prevention deviceof claim 2 further comprising: a first sensing port configured toprovide access through the housing to the volume upstream of theupstream shutoff valve; a second sensing port configured to provideaccess through the housing to the volume between the upstream shutoffvalve and the check valve; a third sensing port configured to provideaccess through the housing to the volume between the check valve and thedownstream check valve; and a fourth sensing port configured to provideaccess through the housing to the volume between the downstream checkvalve and the downstream shutoff valve.
 6. The backflow preventiondevice of claim 1 further comprising an elastomer disk in the clapper ofthe check valve module, the elastomer disk sealing the mating of theclapper with the orifice.
 7. The backflow prevention device of claim 6further comprising a lip located on the outer edge of the orifice of thecheck valve module configured to sealingly engage the elastomer disk. 8.A backflow prevention device, the backflow prevention device comprising:a housing defining a water flow stream; an upstream shutoff valve,wherein the upstream shutoff valve is configured to allow a user tocontrol the water flow stream through the housing; a check valve module:located within the housing downstream of the upstream shutoff valve; andincluding: an orifice, wherein the orifice is configured to allow thewater flow stream through the check valve module; and a clapper, whereinthe clapper is configured to: allow the water flow stream through theorifice when open; and prevent the water flow stream through the orificewhen in a closed position by mating with the orifice; a fulcrumapparatus about which the clapper is allowed to rotate; a rotationalconstraint apparatus which directs the rotation of the clapper; and alateral constraint apparatus which constrains the fulcrum apparatus tomove upstream and downstream relative to the orifice; wherein the motionof the clapper from the closed position to the open position is a hybridmotion; a downstream shutoff valve: located downstream of the checkvalve module; and configured to allow a user to control the water flowstream through the housing.
 9. The backflow prevention device of claim8, wherein the rotational constraint apparatus includes a rotationallinkage attached to the clapper of the check valve module, wherein therotational linkage is attached offset relative to the rotational axiscreated by the fulcrum apparatus.
 10. The backflow prevention device ofclaim 8, wherein the rotational constraint apparatus is upstream of themating of the clapper with the orifice in the closed position.
 11. Thebackflow prevention device of claim 8, wherein the lateral constraintapparatus is downstream of the mating of the clapper with the orifice inthe closed position.
 12. The backflow prevention device of claim 8,wherein the fulcrum apparatus is downstream of the mating of the clapperwith the orifice in the closed position.
 13. A backflow preventiondevice, the backflow prevention device comprising: a housing defining awater flow stream; an upstream shutoff valve, wherein the upstreamshutoff valve is configured to allow a user to control the water flowstream through the housing; a check valve module: located within thehousing downstream of the upstream shutoff valve; and including: a seatconfigured to mate with a portion of the housing; an orifice, whereinthe orifice is configured to allow the water flow stream through thecheck valve module; and a clapper, wherein the clapper is configured to:allow the water flow stream through the orifice when open; and preventthe water flow stream through the orifice when in a closed position bymating with the orifice; a fulcrum apparatus about which the clapper isallowed to rotate; a rotational constraint apparatus which directs therotation of the clapper; a lateral constraint apparatus which constrainsthe fulcrum apparatus to move upstream and downstream relative to theorifice; and a bias configured to hold the clapper in the closedposition a predetermined upstream pressure exists; wherein the motion ofthe clapper from the closed position to the open position is a hybridmotion; and a downstream shutoff valve: located downstream of the checkvalve module; and configured to allow a user to control the water flowstream through the housing.
 14. The backflow prevention device of claim13, wherein the lateral constraint apparatus of the check valve moduleincludes a guide.
 15. The backflow prevention device of claim 14,wherein the guide includes a slot extending perpendicularly from theseat of the check valve module, the fulcrum being slidably mountedwithin the slot.
 16. The backflow prevention device of claim 15, whereinthe fulcrum apparatus includes a pin at least partially extendingthrough the slot.
 17. The backflow prevention device of claim 13,wherein the bias includes a spring.